tag:blogger.com,1999:blog-6676835811534572362.post8122199060074113269..comments2024-02-06T10:02:20.731-06:00Comments on EVTV.ME: New BlogJack Rickardhttp://www.blogger.com/profile/15936311474215791697noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-6676835811534572362.post-57579170796939091582009-10-20T17:18:11.593-05:002009-10-20T17:18:11.593-05:00Hi Jack,
I am enjoying your blog and videos. It ...Hi Jack,<br /><br />I am enjoying your blog and videos. It has gotten me excited to get back to work on my car, which has been a bit neglected lately because of other projects.<br /><br />I like your open attitude- it reminds me a lot more of the Aussie EV scene, rather that the proprietary mentality of trying to capitalize on the "Next Big Thing"<br /><br />Cheers,Will Brunnerhttp://kermitthecar.blogspot.com/noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-34502263066429653892009-07-19T10:52:47.895-05:002009-07-19T10:52:47.895-05:00Tom:
It's precisely the formula I used to cal...Tom:<br /><br />It's precisely the formula I used to calculate the range of the Speedster originally. I like it because it allows you to basically factor out all the more technical issues of air resistance, rolling resistance, drag coefficients etc into the mpg the car actually got. <br /><br />Of course your mileage may vary. That's where the term came from. How you drive a car is very much a part of how energy efficient it becomes. But we have some pretty good numbers in that mpg average from the ICE world.<br /><br />Broadly, the formula derives from the fact that a gallon of gasoline contains approximately 32kWh of energy, and an ICE drivetrain is roughly 25% efficient. Electric drives are more like 88%. So a rough rule of thumb is that it takes 8kWh of electricity equivalent to equal a gallon of gasoline.<br /><br />The car is what it is. An Escalade gets 11 mpg and a Porsche Speedster 30.<br /><br />With the battery upgrade just completed, I have a topped out storage of 23,328 wH. That's the equivalent of 2.9 gallons of gasoline or 87 miles. I have the range at 85 miles. I can do a hundred with careful driving, but that is taking the batteries to pretty much done in.<br /><br />To protect the batteries, I do not want to remove more than 80% of the charge to attain 2000 cycles and that would be about 80 miles. To get 3000 cycles, I would have to limit that to 70% or 70 miles per charge.<br /><br />In practice, unless I'm testing the car on purpose, I drive about 30 miles per day. Going full range occasionally does little harm.<br /><br />It is interesting to note that the Mini-E lease program touted the Mini-E as getting 150 miles per charge. As we are now working on a Clubman conversion, I have been scratching my ass and picking my nose on how they did that, and just can't come up with a way to do it within the laws of physics. So I just assumed they must be a lot smarter than I am.<br /><br /> Now that the cars are out, users are reporting 100 miles as pretty much it, and more like 70 if they use the aircon or heat. BMW allows that they were using some "different criteria" to come up with the 150 mile figure. Go figure.<br /><br />Jack RickardJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-69673318403866181572009-07-07T20:36:52.439-05:002009-07-07T20:36:52.439-05:00So Jack:
First, thanks for the real-world data po...So Jack:<br /><br />First, thanks for the real-world data points and your forward approach. That's a huge contribution to the game.<br /><br />Second, there's a planning number I'm evaluating that would be very useful if accurate. I've seen it said that 8 kWh of LiFePO4 batteries, skipping lots of math, but more or less accounting for everything, is the rough equivalent of about a gallon of gasoline. Not Btu equivalent, not energy equivalent, not to 80% DOD, but a simple rule-of-thumb in-service performance equivalent. That would certainly be a useful rule for planning a conversion.<br /><br />I've been looking at a number of LiFePO4 cars with published data points to try to validate that number. A quick check of the various LiFePO4 powered cars on the EV Album with reported range shows a fairly close adherence to this rough rule, regardless of voltage, AC or DC, or gross weight. Just look at the vehicle, look up or estimate the MPG of the glider, find the kWh rating of the pack at 3.2V, and the reported range is around the kVh/8*mpg. Ef course, it is much harder to say whether this equivalency holds up when we are talking about speed as well as range.<br /><br />Your Beck 356 seems right about there on the range side. It probably got about 30 mpg average with the ICE, which if we count your 21kWh pack (or call it 18 1/2 at a more commonly accepted lower nominal voltage value like 3.2) as 2 1/3 or so gallons, your 85-100 mile range. My question for is two-fold: Initially, what's your impression of the accuracy and usefulness of this equivalency number as to range. <br /><br />More importantly, do you think the number holds up factoring in how you drive the car? If you lead-foot it, I would expect your ICE mileage would have slipped to 20mpg. If your current range is less than 50 miles in teenager mode, the 8kWh/Gal number would seem very useful indeed.<br /><br />Not that you would rely on this for calculating requirements for an expensive pack or anything, but it does seem to simplify the Wh/mi and efficiency corrections and all that. Its a good rule for thinking how many pounds of battery you need to go about how far in a given glider, especially in the absence of a good Wh/mi guess, which is hard to make in the design phase, yes?<br /><br />Whaddya think?<br /><br />Tom AlvaryTom Alvarynoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-27017474410089170652009-06-25T15:00:45.607-05:002009-06-25T15:00:45.607-05:00Wow! 100 miles is a great achievement and for suc...Wow! 100 miles is a great achievement and for such a beautiful EV! I hope you get some serious press coverage of that machine. It would be an inspiration to others for the EV movement.Robert Greenhttp://www.rbgrn.net/noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-74305889219815823622009-05-07T00:04:00.000-05:002009-05-07T00:04:00.000-05:00The explanation of the basics of how electricity w...The explanation of the basics of how electricity works is simple enough. The basis for computations & hotlinks are beneficial, too. All quite helpful.<br /><br />I'm going to view the video for a 3rd time. I would have skipped to the end like you suggested, but it took so long(maybe 30-45 minutes)to buffer, that I just went ahead & watched the whole thing. I get a little more from it every time.<br /><br />Many thanks for the work you've done & for what you will do.<br /><br />MarkMark Farmerhttps://www.blogger.com/profile/06581102593348262738noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-14490605993104579942009-05-04T02:28:00.000-05:002009-05-04T02:28:00.000-05:00Thanks for this blog, Jack. I'd wondered what the ...Thanks for this blog, Jack. I'd wondered what the years had been like for you before we met in 2007. Was it? Thank you, Dick, for suggesting I meet Jack.<br />I was impressed with what I understood of the EV video.<br />Thanks for sharing,<br /> <br />MarkMark Farmerhttps://www.blogger.com/profile/06581102593348262738noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-53861766535549739722009-05-03T01:33:00.000-05:002009-05-03T01:33:00.000-05:00The ePorsche is saweet! The Mini Cooper will be so...The ePorsche is saweet! The Mini Cooper will be something to watch. Next, an electric bicycle/scooter/motorcycle. I'm hooked!<br /><br />Mark F.Mark Farmerhttps://www.blogger.com/profile/06581102593348262738noreply@blogger.com